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Walz A, Stoiber K, Huettig A, Schlichting H, Barth JV. Navigate Flying Molecular Elephants Safely to the Ground: Mass-Selective Soft Landing up to the Mega-Dalton Range by Electrospray Controlled Ion-Beam Deposition. Anal Chem 2022; 94:7767-7778. [PMID: 35609119 PMCID: PMC9178560 DOI: 10.1021/acs.analchem.1c04495] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The prototype of a highly versatile and efficient preparative mass spectrometry system used for the deposition of molecules in ultrahigh vacuum (UHV) is presented, along with encouraging performance data obtained using four model species that are thermolabile or not sublimable. The test panel comprises two small organic compounds, a small and very large protein, and a large DNA species covering a 4-log mass range up to 1.7 MDa as part of a broad spectrum of analyte species evaluated to date. Three designs of innovative ion guides, a novel digital mass-selective quadrupole (dQMF), and a standard electrospray ionization (ESI) source are combined to an integrated device, abbreviated electrospray controlled ion-beam deposition (ES-CIBD). Full control is achieved by (i) the square-wave-driven radiofrequency (RF) ion guides with steadily tunable frequencies, including a dQMF allowing for investigation, purification, and deposition of a virtually unlimited m/z range, (ii) the adjustable landing energy of ions down to ∼2 eV/z enabling integrity-preserving soft landing, (iii) the deposition in UHV with high ion beam intensity (up to 3 nA) limiting contaminations and deposition time, and (iv) direct coverage control via the deposited charge. The maximum resolution of R = 650 and overall efficiency up to Ttotal = 4.4% calculated from the solution to UHV deposition are advantageous, whereby the latter can be further enhanced by optimizing ionization performance. In the setup presented, a scanning tunneling microscope (STM) is attached for in situ UHV investigations of deposited species, demonstrating a selective, structure-preserving process and atomically clean layers.
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Affiliation(s)
- Andreas Walz
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Karolina Stoiber
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Annette Huettig
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Hartmut Schlichting
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Johannes V Barth
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
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2
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Schio L, Forrer D, Casarin M, Goldoni A, Rogero C, Vittadini A, Floreano L. On surface chemical reactions of free-base and titanyl porphyrins with r-TiO 2(110): a unified picture. Phys Chem Chem Phys 2022; 24:12719-12744. [PMID: 35583960 DOI: 10.1039/d2cp01073a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this Perspective we present a comprehensive study of the multiple reaction products of metal-free porphyrins (2H-Ps) in contact with the rutile TiO2(110) surface. In the absence of peripheral functionalization with specific linkers, the porphyrin adsorption is driven by the coordination of the two pyrrolic nitrogen atoms of the macrocycle to two consecutive oxygen atoms of the protruding Obr rows via hydrogen bonding. This chemical interaction favours the iminic nitrogen uptake of hydrogen from near surface layers at room temperature, thus yielding a stable acidic porphyrin (4H-P). In addition, a mild annealing (∼100 °C) triggers the incorporation of a Ti atom in the porphyrin macrocycle (self-metalation). We recently demonstrated that such a low temperature reaction is driven by a Lewis base iminic attack, which lowers the energy barriers for the outdiffusion of Ti interstitial atoms (Tiint) [Kremer et al., Appl. Surf. Sci., 2021, 564, 150403]. In the monolayer (ML) range, the porphyrin adsorption site, corresponding to a TiO-TPP configuration, is extremely stable and tetraphenyl-porphyrins (TPPs) may even undergo conformational distortion (flattening) by partial cyclo-dehydrogenation, while remaining anchored to the O rows up to 450 °C [Lovat et al., Nanoscale, 2017, 9, 11694]. Here we show that, upon self-metalation, isolated molecules at low coverage may jump atop the rows of five-fold coordinated Ti atoms (Ti5f). This configuration is associated with the formation of a new coordination complex, Ti-O-Ti5f, as determined by comparison with the deposition of pristine titanyl-porphyrin (TiO-TPP) molecules. The newly established Ti-O-Ti5f anchoring configuration is found to be stable also beyond the TPP flattening reaction. The anchoring of TiO-TPP to the Ti5f rows is, however, susceptible to the cross-talk between phenyls of adjacent molecules, which ultimately drives the TiO-TPP temperature evolution in the ML range along the same pathway followed by 2H-TPP.
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Affiliation(s)
- Luca Schio
- CNR-IOM, Laboratorio TASC, Basovizza S.S. 14, Km 163.5, I-34149 Trieste, Italy.
| | - Daniel Forrer
- CNR-ICMATE and INSTM, via Marzolo 1, I-35131 Padova, Italy.
| | - Maurizio Casarin
- CNR-ICMATE and INSTM, via Marzolo 1, I-35131 Padova, Italy. .,Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I-35131 Padova, Italy
| | - Andrea Goldoni
- Elettra-Sincrotrone Trieste S.C.p.A., Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - Celia Rogero
- Materials Physics Center MPC, Centro de Física de Materiales (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), E-20018 San Sebastian, Spain
| | | | - Luca Floreano
- CNR-IOM, Laboratorio TASC, Basovizza S.S. 14, Km 163.5, I-34149 Trieste, Italy.
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Lai J, Wang C, Xing Z, Lu S, Chen Q, Chen L. Quantitative amplitude-modulation scanning Kelvin probe microscopy via the second eigenmode excitation. Ultramicroscopy 2021; 230:113399. [PMID: 34610537 DOI: 10.1016/j.ultramic.2021.113399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/28/2021] [Accepted: 09/20/2021] [Indexed: 11/15/2022]
Abstract
Amplitude modulation scanning Kelvin probe microscopy (AM-SKPM) is widely used to measure the contact potential difference (CPD) between probe and samples in ambient or dry inert atmosphere. However, AM-SKPM is generally considered quantitatively inaccurate due to crosstalk between the cantilever and the sample. Here we demonstrate that the accuracy of AM-SKPM-based CPD measurements is drastically improved by exciting the SKPM probe at its second eigenmode. In the second eigenmode of oscillation, there exists a stationary node at the cantilever towards its free end, across which the displacement bears opposite signs; therefore driving the SKPM probe at its second eigenmode helps to partially cancel the virtual work done by the cantilever and reduce the crosstalk effect. The improvement in accuracy is experimentally confirmed with interdigitating electrodes calibration samples as well as practical samples such as the cross-section of wafer-bonded GaAs/GaN heterojunction.
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Affiliation(s)
- Junqi Lai
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China; i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Cheng Wang
- i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China; School of Physical Science and Technology, Shanghai Tech University, Shanghai 201210, China
| | - Zhiwei Xing
- Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Shulong Lu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China; Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Qi Chen
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China; i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
| | - Liwei Chen
- i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China; In-situ Center for Physical Sciences, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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4
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Wähler T, Schuster R, Libuda J. Self-Metalation of Anchored Porphyrins on Atomically Defined Cobalt Oxide Surfaces: In situ Studies by Surface Vibrational Spectroscopy. Chemistry 2020; 26:12445-12453. [PMID: 32333716 PMCID: PMC7590103 DOI: 10.1002/chem.202001331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Indexed: 12/20/2022]
Abstract
Metalation of anchored porphyrins is essential for their functionality at hybrid interfaces. In this work, we have studied the anchoring and metalation of a functionalized porphyrin derivative, 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin (MCTPP), on an atomically-defined CoO(100) film under ultrahigh vacuum (UHV) conditions. We follow both the anchoring to the oxide surface and the self-metalation by surface Co2+ ions via infrared reflection absorption spectroscopy (IRAS). At 150 K, MCTPP multilayer films adsorb molecularly on CoO(100) without anchoring to the surface. Upon heating to 195 K, the first layer of porphyrin molecules anchors via formation of a bridging surface carboxylate. Above 460 K, the MCTPP multilayer desorbs and only the anchored monolayer resides on the surface up to temperatures of 600 K approximately. The orientation of anchored MCTPP depends on the surface coverage. At low coverage, the MCTPP adopts a nearly flat-lying geometry, whereas an upright standing film is formed near the multilayer coverage. Self-metalation of MCTPP depends critically on the surface temperature, the coverage and on the molecular orientation. At 150 K, metalation is largely suppressed, while the degree of metalation increases with increasing temperature and reaches a value of around 60 % in the first monolayer at 450 K. At lower coverage higher metalation fractions (85 % and above) are observed, similar as for increasing temperature.
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Affiliation(s)
- Tobias Wähler
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Ralf Schuster
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Jörg Libuda
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
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5
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Bodek L, Engelund M, Cebrat A, Such B. Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO 2. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:821-828. [PMID: 32551207 PMCID: PMC7277932 DOI: 10.3762/bjnano.11.67] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
The adsorption behavior of tin phthalocyanine (SnPc) molecules on rutile TiO2(110) was studied by scanning tunneling microscopy (STM). Low-temperature STM measurements of single molecules reveal the coexistence of two conformations of molecules on the TiO2 surface. Density functional theory-based simulations (DFT) indicate that the difference originates from the position of the tin atom protruding from the molecule plane. The irreversible switching of Sn-up molecules into the Sn-down conformation was observed either after sample annealing at 200 °C or as a result of tip-induced manipulation. Room-temperature measurements conducted for a coverage of close to a monolayer showed no tendency for molecular arrangement.
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Affiliation(s)
- Lukasz Bodek
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Lojasiewicza 11, 30-348 Krakow, Poland
| | - Mads Engelund
- Espeem S.A.R.L., c/o Technoport S.A., 9 Avenue des Haut-Fourneaux, L-4362 Esch-Sur-Alzette, Luxembourg
| | - Aleksandra Cebrat
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Lojasiewicza 11, 30-348 Krakow, Poland
- EMPA, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Bartosz Such
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Lojasiewicza 11, 30-348 Krakow, Poland
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Wrana D, Cieślik K, Belza W, Rodenbücher C, Szot K, Krok F. Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:1596-1607. [PMID: 31467822 PMCID: PMC6693395 DOI: 10.3762/bjnano.10.155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
Controlling the work function of transition metal oxides is of key importance with regard to future energy production and storage. As the majority of applications involve the use of heterostructures, the most suitable characterization technique is Kelvin probe force microscopy (KPFM), which provides excellent energetic and lateral resolution. In this paper, we demonstrate precise characterization of the work function using the example of artificially formed crystalline titanium monoxide (TiO) nanowires on strontium titanate (SrTiO3) surfaces, providing a sharp atomic interface. The measured value of 3.31(21) eV is the first experimental work function evidence for a cubic TiO phase, where significant variations among the different crystallographic facets were also observed. Despite the remarkable height of the TiO nanowires, KPFM was implemented to achieve a high lateral resolution of 15 nm, which is close to the topographical limit. In this study, we also show the unique possibility of obtaining work function and conductivity maps on the same area by combining noncontact and contact modes of atomic force microscopy (AFM). As most of the real applications require ambient operating conditions, we have additionally checked the impact of air venting on the work function of the TiO/SrTiO3(100) heterostructure, proving that surface reoxidation occurs and results in a work function increase of 0.9 eV and 0.6 eV for SrTiO3 and TiO, respectively. Additionally, the influence of adsorbed surface species was estimated to contribute 0.4 eV and 0.2 eV to the work function of both structures. The presented method employing KPFM and local conductivity AFM for the characterization of the work function of transition metal oxides may help in understanding the impact of reduction and oxidation on electronic properties, which is of high importance in the development of effective sensing and catalytic devices.
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Affiliation(s)
- Dominik Wrana
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Karol Cieślik
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Wojciech Belza
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Christian Rodenbücher
- Institute of Energy and Climate Research (IEK-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Krzysztof Szot
- Peter Grünberg Institute (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- August Chelkowski Institute of Physics, University of Silesia, 40–007 Katowice, Poland
| | - Franciszek Krok
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
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7
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Freund S, Hinaut A, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:874-881. [PMID: 31165014 PMCID: PMC6541355 DOI: 10.3762/bjnano.10.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Properties of metal oxides, such as optical absorption, can be influenced through the sensitization with molecular species that absorb visible light. Molecular/solid interfaces of this kind are particularly suited for the development and design of emerging hybrid technologies such as dye-sensitized solar cells. A key optimization parameter for such devices is the choice of the compounds in order to control the direction and the intensity of charge transfer across the interface. Here, the deposition of two different molecular dyes, porphyrin and coumarin, as single-layered islands on a NiO(001) single crystal surface have been studied by means of non-contact atomic force microscopy at room temperature. Comparison of both island types reveals different adsorption and packing of each dye, as well as an opposite charge-transfer direction, which has been quantified by Kelvin probe force microscopy measurements.
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Affiliation(s)
- Sara Freund
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Nathalie Marinakis
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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8
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Stable contrast mode on TiO 2(110) surface with metal-coated tips using AFM. Ultramicroscopy 2018; 191:51-55. [PMID: 29803917 DOI: 10.1016/j.ultramic.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/19/2018] [Accepted: 04/04/2018] [Indexed: 11/20/2022]
Abstract
We investigated a method to obtain a stable contrast mode on the TiO2(110) surface. The stable contrast rate is approximately 95% with a W-coated Si cantilever, which demonstrates that a stable tip apex plays an important role to obtain the real geometry of the surface during atomic force microscopy measurement. Information related to surface structure and tunnelling current on the TiO2(110) surface can be obtained by the W-coated Si cantilever. It is possible to investigate the electronic structure and surface potential on the TiO2(110) surface with atomic resolution. In particular, the proposed method could be widely applied to investigate the catalytic activity and the mechanism of a catalytic reaction by a metal-coated tip in the future.
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9
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Freund S, Hinaut A, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:242-249. [PMID: 29441269 PMCID: PMC5789385 DOI: 10.3762/bjnano.9.26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/25/2017] [Indexed: 05/26/2023]
Abstract
The properties of metal oxides, such as charge-transport mechanisms or optoelectronic characteristics, can be modified by functionalization with organic molecules. This kind of organic/inorganic surface is nowadays highly regarded, in particular, for the design of hybrid devices such as dye-sensitized solar cells. However, a key parameter for optimized interfaces is not only the choice of the compounds but also the properties of adsorption. Here, we investigated the deposition of an organic dye precursor molecule on a NiO(001) single crystal surface by means of non-contact atomic force microscopy at room temperature. Depending on the coverage, single molecules, groups of adsorbates with random or recognizable shapes, or islands of closely packed molecules were identified. Single molecules and self assemblies are resolved with submolecular resolution showing that they are lying flat on the surface in a trans-conformation. Within the limits of our Kelvin probe microscopy setup a charge transfer from NiO to the molecular layer of 0.3 electrons per molecules was observed only in the areas where the molecules are closed packed.
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Affiliation(s)
- Sara Freund
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Nathalie Marinakis
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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10
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Jöhr R, Hinaut A, Pawlak R, Zajac Ł, Olszowski P, Such B, Glatzel T, Zhang J, Muntwiler M, Bergkamp JJ, Mateo LM, Decurtins S, Liu SX, Meyer E. Thermally induced anchoring of a zinc-carboxyphenylporphyrin on rutile TiO2 (110). J Chem Phys 2017. [DOI: 10.1063/1.4982936] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Res Jöhr
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Rémy Pawlak
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Łukasz Zajac
- Physics Department, Jagiellonian University, Ul. Prof. St. Lojasiewicza 11, 30-348 Krakow, Poland
| | - Piotr Olszowski
- Physics Department, Jagiellonian University, Ul. Prof. St. Lojasiewicza 11, 30-348 Krakow, Poland
| | - Bartosz Such
- Physics Department, Jagiellonian University, Ul. Prof. St. Lojasiewicza 11, 30-348 Krakow, Poland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Jun Zhang
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | | | - Jesse J. Bergkamp
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Luis-Manuel Mateo
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Silvio Decurtins
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Shi-Xia Liu
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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11
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Olszowski P, Zajac L, Godlewski S, Such B, Pawlak R, Hinaut A, Jöhr R, Glatzel T, Meyer E, Szymonski M. Ordering of Zn-centered porphyrin and phthalocyanine on TiO 2(011): STM studies. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:99-107. [PMID: 28144569 PMCID: PMC5238625 DOI: 10.3762/bjnano.8.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/21/2016] [Indexed: 05/04/2023]
Abstract
Zn(II)phthalocyanine molecules (ZnPc) were thermally deposited on a rutile TiO2(011) surface and on Zn(II)meso-tetraphenylporphyrin (ZnTPP) wetting layers at room temperature and after elevated temperature thermal processing. The molecular homo- and heterostructures were characterized by high-resolution scanning tunneling microscopy (STM) at room temperature and their geometrical arrangement and degree of ordering are compared with the previously studied copper phthalocyanine (CuPc) and ZnTPP heterostructures. It was found that the central metal atom may play some role in ordering and growth of phthalocyanine/ZnTPP heterostructures, causing differences in stability of upright standing ZnPc versus CuPc molecular chains at given thermal annealing conditions.
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Affiliation(s)
- Piotr Olszowski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Lukasz Zajac
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Szymon Godlewski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Bartosz Such
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
| | - Rémy Pawlak
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Res Jöhr
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Thilo Glatzel
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Ernst Meyer
- University of Basel, Department of Physics, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Marek Szymonski
- Research Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, Poland
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12
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Kou L, Li YJ, Kamijyo T, Naitoh Y, Sugawara Y. Investigation of the surface potential of TiO 2 (110) by frequency-modulation Kelvin probe force microscopy. NANOTECHNOLOGY 2016; 27:505704. [PMID: 27861162 DOI: 10.1088/0957-4484/27/50/505704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We investigate the surface potential distribution on a TiO2 (110)-1 × 1 surface by Kelvin probe force microscopy (KPFM) and atom-dependent bias-distance spectroscopic mapping. The experimental results demonstrate that the local contact potential difference increases on twofold-coordinated oxygen sites, and decreases on OH defects and fivefold-coordinated Ti sites. We propose a qualitative model to explain the origin of the surface potential of TiO2 (110). We qualitatively calculate the surface potential induced by chemical potential and permanent surface dipole. The calculated results agree with our experimental ones. Therefore, we suggest that the surface potential of TiO2 (110) is dominated not only by the permanent surface dipole between the tip apex atom and surface, but also by the dipoles induced by the chemical interaction between the tip and sample. The KPFM technique demonstrate the possibility of investigation of the charge transfer phenomenon on TiO2 surface under gas conditions. It is useful for the elucidation of the mechanism of the catalytic reactions.
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Affiliation(s)
- Lili Kou
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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13
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Prauzner-Bechcicki JS, Zajac L, Olszowski P, Jöhr R, Hinaut A, Glatzel T, Such B, Meyer E, Szymonski M. Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:1642-1653. [PMID: 28144513 PMCID: PMC5238678 DOI: 10.3762/bjnano.7.156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
Titanium dioxide, or titania, sensitized with organic dyes is a very attractive platform for photovoltaic applications. In this context, the knowledge of properties of the titania-sensitizer junction is essential for designing efficient devices. Consequently, studies on the adsorption of organic dyes on titania surfaces and on the influence of the adsorption geometry on the energy level alignment between the substrate and an organic adsorbate are necessary. The method of choice for investigating the local environment of a single dye molecule is high-resolution scanning probe microscopy. Microscopic results combined with the outcome of common spectroscopic methods provide a better understanding of the mechanism taking place at the titania-sensitizer interface. In the following paper, we review the recent scanning probe microscopic research of a certain group of molecular assemblies on rutile titania surfaces as it pertains to dye-sensitized solar cell applications. We focus on experiments on adsorption of three types of prototypical dye molecules, i.e., perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), phtalocyanines and porphyrins. Two interesting heteromolecular systems comprising molecules that are aligned with the given review are discussed as well.
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Affiliation(s)
- Jakub S Prauzner-Bechcicki
- Research Centre for Nanometer-scale Science and Advanced Materials (NANOSAM), Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Lukasz Zajac
- Research Centre for Nanometer-scale Science and Advanced Materials (NANOSAM), Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Piotr Olszowski
- Research Centre for Nanometer-scale Science and Advanced Materials (NANOSAM), Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Res Jöhr
- Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland
| | - Bartosz Such
- Research Centre for Nanometer-scale Science and Advanced Materials (NANOSAM), Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland
| | - Marek Szymonski
- Research Centre for Nanometer-scale Science and Advanced Materials (NANOSAM), Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
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14
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Hehn I, Schuster S, Wächter T, Abu-Husein T, Terfort A, Zharnikov M, Zojer E. Employing X-ray Photoelectron Spectroscopy for Determining Layer Homogeneity in Mixed Polar Self-Assembled Monolayers. J Phys Chem Lett 2016; 7:2994-3000. [PMID: 27429041 PMCID: PMC4976398 DOI: 10.1021/acs.jpclett.6b01096] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/18/2016] [Indexed: 05/24/2023]
Abstract
Self-assembled monolayers (SAMs) containing embedded dipolar groups offer the particular advantage of changing the electronic properties of a surface without affecting the SAM-ambient interface. Here we show that such systems can also be used for continuously tuning metal work functions by growing mixed monolayers consisting of molecules with different orientations of the embedded dipolar groups. To avoid injection hot-spots when using the SAM-modified electrodes in devices, a homogeneous mixing of the two components is crucial. We show that a combination of high-resolution X-ray photoelectron spectroscopy with state-of-the-art simulations is an ideal tool for probing the electrostatic homogeneity of the layers and thus for determining phase separation processes in polar adsorbate assemblies down to inhomogeneities at the molecular level.
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Affiliation(s)
- Iris Hehn
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Swen Schuster
- Angewandte
Physikalische Chemie, Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Tobias Wächter
- Angewandte
Physikalische Chemie, Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Tarek Abu-Husein
- Institut
für Anorganische und Analytische Chemie, Universität Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany
| | - Andreas Terfort
- Institut
für Anorganische und Analytische Chemie, Universität Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany
| | - Michael Zharnikov
- Angewandte
Physikalische Chemie, Universität
Heidelberg, Im Neuenheimer
Feld 253, 69120 Heidelberg, Germany
| | - Egbert Zojer
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
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15
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Pilet N, Lisunova Y, Lamattina F, Stevenson SE, Pigozzi G, Paruch P, Fink RH, Hug HJ, Quitmann C, Raabe J. A single probe for imaging photons, electrons and physical forces. NANOTECHNOLOGY 2016; 27:235705. [PMID: 27146329 DOI: 10.1088/0957-4484/27/23/235705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.
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Affiliation(s)
- Nicolas Pilet
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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16
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Zając Ł, Olszowski P, Godlewski S, Such B, Jöhr R, Pawlak R, Hinaut A, Glatzel T, Meyer E, Szymonski M. Ordered heteromolecular overlayers formed by metal phthalocyanines and porphyrins on rutile titanium dioxide surface studied at room temperature. J Chem Phys 2016; 143:224702. [PMID: 26671391 DOI: 10.1063/1.4936658] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular heterostructures are formed from meso-tetraphenyl porphyrins-Zn(II) (ZnTPP) and Cu(II)-phthalocyanines (CuPc) on the rutile TiO2(011) surface. We demonstrate that ZnTPP molecules form a quasi-ordered wetting layer with flat-lying molecules, which provides the support for growth of islands comprised of upright CuPc molecules. The incorporation of the ZnTPP layer and the growth of heterostructures increase the stability of the system and allow for room temperature scanning tunneling microscopy (STM) measurements, which is contrasted with unstable STM probing of only CuPc species on TiO2. We demonstrate that within the CuPc layer the molecules arrange in two phases and we identify molecular dimers as basic building blocks of the dominant structural phase.
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Affiliation(s)
- Łukasz Zając
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Piotr Olszowski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Szymon Godlewski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Bartosz Such
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
| | - Res Jöhr
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Rémy Pawlak
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Marek Szymonski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. S. Łojasiewicza 11, 30-348 Krakow, Poland
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